Multi-axis prosthetic ankle

ABSTRACT

A multi-axis prosthetic ankle for connection of a prosthetic lower leg to a prosthetic foot. A substantially hollow prosthetic foot connection component includes a receiving cavity for receiving a portion of a lower leg connection component. A retainer or retainer assembly is preferably installed into the receiving cavity to help retain the lower leg connection component therein. Once the necessary components are in place, the remainder of the receiving cavity is substantially filled with an elastomeric material. An external bearing may reside atop the elastomeric material and act in conjunction with the elastomeric material to control ankle flexion.

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/770,833, filed on Feb. 3, 2004, which is acontinuation-in-part of U.S. patent application Ser. No. 09/893,887,filed on Jun. 29, 2001, now U.S. Pat. No. 6,699,295, issued Mar. 2,2004.

BACKGROUND OF THE INVENTION

The present invention relates generally to prosthetic devices, and moreparticularly to multi-axis prosthetic ankles.

A prosthetic ankle is a component which connects a prosthetic foot witha prosthetic lower leg. For smooth walking, especially, across unevenground, it is important for the ankle to be designed for a full range offoot motion with respect to the lower leg prosthesis. One embodiment ofsuch an ankle is described in U.S. patent application Ser. No.09/893,887, which is hereby incorporated by reference herein. Mostprosthetic ankles currently on the market, however, do not provideoptimally controlled multi-axis motion. Often the prosthetic ankle hassuch a low stiffness that it effectively reduces any functionalcapabilities of the attached prosthetic foot, resulting in a choppy,unnatural and uncomfortable gait. Some ankles require adjustments to theassembly in order to achieve the desired function.

A full range of motion may be accomplished by the use of multiple axesof rotation in the ankle joint. However, conventional prosthetic anklejoints that provide multi-axis motion tend to require extensivemaintenance including the replacement of parts in order to functionproperly. This is because the conventional ankle joint designs requireelastic members to slide in contact with either a rigid surface, whichis typically metallic, or another elastic surface. Thissurface-to-surface sliding motion is the primary cause of materialbreakdown.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide amulti-axis prosthetic ankle joint which does not suffer from theshortcomings of the prior art.

One embodiment of a multi-axis prosthetic ankle joint of the presentinvention includes a bottom component adapted to be connected to aprosthetic foot, a lower leg connection component adapted to beconnected to a prosthetic lower leg, an elastomeric material securelyconnecting the bottom component with the lower leg connection component,and a mechanical device suspended in the elastomeric material. In thisembodiment, the mechanical device comprises a first rigid elementconnected to the bottom component but not to the lower leg connectioncomponent, and a second rigid element connected to the lower legconnection component but not to the bottom component. The first andsecond elements interlockingly float in the elastomeric material, andare not in direct contact with one another, so as to permit relativemovement of the bottom component and the lower leg connection componentby deformation of the elastomeric material.

In this particular embodiment of the present invention, the mechanicaldevice comprises a generally U-shaped first part connected to the bottomcomponent so as to define a first aperture, and a generally U-shapedsecond part connected to the lower leg connection component so as todefine a second aperture. The first part floatingly extends through thesecond aperture, and the second part floatingly extends through thefirst aperture.

An alternate embodiment of a multi-axis prosthetic ankle of the presentinvention may also include a bottom, prosthetic foot connectioncomponent adapted to be connected to a prosthetic foot, a lower legconnection component adapted to be connected to a prosthetic lower leg,an elastomeric material securely connecting the prosthetic footconnection component with the lower leg connection component, and amechanical device suspended in the elastomeric material. In thisembodiment, the mechanical device comprises a first rigid element in theprosthetic foot connection component that is not connected to the lowerleg connection component, and a second rigid element connected to thelower leg connection component but not to the prosthetic foot connectioncomponent. The position of the first and second elements is maintainedby the elastomeric material. The first element may act as a stop forrestricting the range of motion of the lower leg connection component,but otherwise the first and second elements are not in direct contactwith one another. As such, relative movement of the prosthetic footconnection component and the lower leg connection component occursthrough deformation of the elastomeric material.

In this particular embodiment of the present invention, the mechanicaldevice comprises a cavity in the prosthetic foot connection componentthat is substantially defined by a plurality of vertically extendingwalls, and a generally hook-shaped projection extending from the lowerleg connection component. The hook-shaped projection of the lower legconnection component floatingly resides within the cavity in theprosthetic foot connection component. Contact between a portion of thehook-shaped projection and a rigid wall of the prosthetic footconnection component can be utilized to restrict the range of motion ofthe lower leg connection component. Other points of contact between thelower leg connection component and the prosthetic foot connectioncomponent may be similarly utilized.

By terms such as “interlockingly float” and “floatingly resides” it ismeant that the first and second elements are suspended in theelastomeric material in close relation to one another, but are retainedin position by the intermediary elastomeric material, not by contactwith one another. Since the deformation of the elastic material permitsmulti-axis relative movement of the bottom component and the lower legconnection component, including translational movement, the ankle jointof the invention can simulate natural ankle motion by providing plantarflexion, dorsi flexion, inversion, eversion, translation andinternal/external rotational movement. Such motion is optimallycontrolled by the multi-axis deformation of the elastic material,without sacrificing the energy return of the prosthetic foot. Further,since the components of the mechanical device are bonded to, and encasedby, the elastomeric material, the ankle has the ability to absorb anddamp both rotational and linear impacts.

As force is applied to either of these ankles, the ankle moves inrotation and translation with a fluid motion by deforming theelastomeric medium. According to a further feature of the invention, atleast one mechanical stop may also be positioned on/in either of thesemulti-axis ankle embodiments to prevent the relative angular movement ofthe ankles from deforming the elastomeric material beyond the elasticlimit thereof. Since the deformation of the elastomeric material in bothmulti-axis ankle embodiments is thus always kept within the elasticlimit, any tendency toward breakdown of the elastomeric material isfurther reduced.

In another embodiment of a multi-axis prosthetic ankle of the presentinvention, the ankle may include a bottom, prosthetic foot connectioncomponent adapted to be connected to a prosthetic foot, a lower legconnection component adapted to be connected to a prosthetic lower leg,an elastomeric material residing between the prosthetic foot connectioncomponent and the lower leg connection component, and a mechanicalconnection suspended in the elastomeric material. In this embodiment,the prosthetic foot connection component and the lower leg connectioncomponent are mechanically coupled and are preferably substantiallyencased within the elastomeric material. A portion of the prostheticfoot connection component may act as a stop for restricting the range ofmotion of the lower leg connection component. Unlike the previouslydescribed exemplary embodiments, this multi-axis ankle embodiment doesnot rely solely on the elastomeric material to maintain the positionalrelationship between the prosthetic foot connection component and thelower leg connection component. Consequently, in this exemplaryembodiment of the present invention, relative movement of the prostheticfoot connection component and the lower leg connection component occursthrough deformation of the elastomeric material as well as through themechanical connection.

In this particular embodiment of the present invention, the mechanicalconnection may comprise a pin that resides in an aperture passingthrough both an upwardly-extending portion of the prosthetic footconnection component and a downwardly-extending projection of the lowerleg connection component. A bearing, such as a spherical bearing, may belocated in the downwardly-extending projection of the lower legconnection component to receive the pin and enhance movement of thelower leg connection component. The upwardly-extending portion of theprosthetic foot connection component may comprise two legs, such thatthe downwardly-extending projection of the lower leg connectioncomponent may reside therebetween. A dorsi-flexion stop may be locatedin the prosthetic foot connection component so as to contact a portionof the downwardly-extending projection of the lower leg connectioncomponent and limit the range of motion thereof. Alternatively, adorsi-flexion stop may be located in a projection of the lower legconnection component and adapted to contact a portion of the prostheticfoot connection component in order to limit ankle movement.

As force is applied to this embodiment of the multi-axis ankle, theankle moves in rotation with a fluid motion by pivoting about the pinand simultaneously deforming the elastomeric material. The ankle is alsoable to move in translation via the inherent tilting ability of thespherical bearing. Since deformation of the elastomeric material in thisembodiment is always kept within the elastic limit by means of thedorsi-flexion stop and the limited translational movement of thedownwardly-extending projection of the lower leg connection component,breakdown of the elastomeric material is minimized.

Since there is no surface-to-surface sliding motion within any of theaforementioned multi-axis prosthetic ankle embodiments, the materialbreakdown which might otherwise occur due to friction therebetween isreduced or eliminated.

According to yet a another embodiment of the present invention, amulti-axis prosthetic ankle may simply comprise a bottom componentadapted to be connected to a prosthetic foot, a lower leg connectioncomponent adapted to be connected to a prosthetic lower leg, anelastomeric material securely connecting the bottom component with thelower leg connection component, and mechanical means for limiting adeformation of the elastic material.

In still another embodiment of the present invention, a multi-axisprosthetic ankle may comprise a bottom component adapted to be connectedto a prosthetic foot, a lower leg connection component adapted to beconnected to a prosthetic lower leg, and an elastomeric materialsecurely connecting the bottom component with the lower leg connectioncomponent. In such an embodiment, deformation of the elastic materialgenerally determines the range of motion of the ankle.

BRIEF DESCRIPTION OF THE DRAWINGS

In addition to the features mentioned above, other aspects of thepresent invention will be readily apparent from the followingdescriptions of the drawings and exemplary embodiments, wherein likereference numerals across the several views refer to identical orequivalent features, and wherein:

FIG. 1 is a top plan view of an exemplary embodiment of a multi-axisprosthetic ankle of the present invention;

FIG. 2 is a front elevation view of the multi-axis prosthetic ankle ofFIG. 1, wherein an elastomeric encasing material is shown in phantomlines for purposes of clarity;

FIG. 3 is a side elevation view of the multi-axis prosthetic ankle ofFIG. 1, wherein the elastomeric encasing material is again shown inphantom lines for purposes of clarity;

FIG. 4 is a top plan view of a lower leg connection component of themulti-axis prosthetic ankle of FIG. 1;

FIG. 5 is a front elevation view of the lower leg connection componentof FIG. 4;

FIG. 6 is a front elevation view of a bracket for mounting to the lowerleg connection component of FIGS. 4-5;

FIG. 7 is a top plan view of a bottom component of the multi-axisprosthetic ankle of FIG. 1;

FIG. 8 is a sectional front elevation view of the multi-axis prostheticankle of FIG. 1, taken along lines A-A of FIG. 7;

FIG. 9 is a sectional isometric view of the multi-axis prosthetic ankleof FIG. 1, taken along lines B-B of FIG. 1;

FIG. 10 is a top plan view of an alternate exemplary embodiment of amulti-axis prosthetic ankle of the present invention, wherein anelastomeric encasing material is shown in phantom lines for purposes ofclarity;

FIG. 11 is a front elevation view of the multi-axis prosthetic ankle ofFIG. 10, wherein the elastomeric encasing material is again shown inphantom lines for purposes of clarity;

FIG. 12 is a side elevation view of the multi-axis prosthetic ankle ofFIG. 10, wherein the elastomeric encasing material is again shown inphantom lines for purposes of clarity;

FIG. 13 is a top plan view of a prosthetic foot connection component ofthe multi-axis prosthetic ankle of FIG. 10;

FIG. 14 is a front elevation view of the prosthetic foot connectioncomponent of FIG. 13;

FIG. 15 is a side elevation view of the prosthetic foot connectioncomponent of FIG. 13;

FIG. 16 is a top plan view of a lower leg connection component of themulti-axis prosthetic ankle of FIG. 10;

FIG. 17 is a front elevation view of the lower leg connection componentof FIG. 16;

FIG. 18 is a side elevation view of the lower leg connection componentof FIG. 16;

FIG. 19 is a sectional side elevation view of the multi-axis prostheticankle of FIG. 10, taken along lines C-C thereof;

FIG. 20 depicts an alternate embodiment of the sectional side elevationview of FIG. 19, wherein a reinforcing section and a retaining pin hasbeen added to the prosthetic foot connection component;

FIG. 21 is a top plan view of another exemplary embodiment of amulti-axis prosthetic ankle of the present invention;

FIG. 22 is a front elevation view of the multi-axis prosthetic ankle ofFIG. 21, wherein an elastomeric encasing material is shown in phantomlines for purposes of clarity;

FIG. 23 is a side elevation view of the multi-axis prosthetic ankle ofFIG. 21, wherein the elastomeric encasing material is again shown inphantom lines for purposes of clarity;

FIG. 24 is a top plan view of a prosthetic foot connection component ofthe multi-axis prosthetic ankle of FIG. 21;

FIG. 25 is a front elevation view of the prosthetic foot connectioncomponent of FIG. 24;

FIG. 26 is a side elevation view of the prosthetic foot connectioncomponent of FIG. 24;

FIG. 27 is a top plan view of a lower leg connection component of themulti-axis prosthetic ankle of FIG. 21;

FIG. 28 is a front elevation view of the lower leg connection componentof FIG. 27;

FIG. 29 is a side elevation view of the lower leg connection componentof FIG. 27;

FIG. 30 is a sectional side elevation view of the multi-axis prostheticankle of FIG. 21, taken along lines D-D thereof;

FIG. 31 is a top plan view of yet another exemplary embodiment of amulti-axis prosthetic ankle of the present invention;

FIG. 32 is a front elevation view of the multi-axis prosthetic ankle ofFIG. 31, wherein an elastomeric encasing material is shown in phantomlines for purposes of clarity;

FIG. 33 is a side elevation view of the multi-axis prosthetic ankle ofFIG. 31, wherein the elastomeric encasing material is again shown inphantom lines for purposes of clarity;

FIG. 34 is a top plan view of a prosthetic foot connection component ofthe multi-axis prosthetic ankle of FIG. 31;

FIG. 35 is a front elevation view of the prosthetic foot connectioncomponent of FIG. 34;

FIG. 36 is a side elevation view of the prosthetic foot connectioncomponent of FIG. 34;

FIG. 37 is a top plan view of a lower leg connection component of themulti-axis prosthetic ankle of FIG. 31;

FIG. 38 is a front elevation view of the lower leg connection componentof FIG. 37;

FIG. 39 is a side elevation view of the lower leg connection componentof FIG. 37;

FIG. 40 is a sectional side elevation view of the multi-axis prostheticankle of FIG. 31, taken along lines E-E thereof;

FIG. 41 a shows the multi-axis prosthetic ankle of FIG. 32 in amid-stance position;

FIG. 41 b shows the multi-axis prosthetic ankle of FIG. 32 in a heelstrike position;

FIG. 41 c shows the multi-axis prosthetic ankle of FIG. 32 in a toe-offposition;

FIG. 42 is a side elevational view of still another exemplary embodimentof a multi-axis prosthetic ankle of the present invention;

FIG. 43 is an exploded view of the multi-axis prosthetic ankle of FIG.42;

FIG. 44 is a top plan view of the multi-axis prosthetic ankle of FIG.42;

FIG. 45 is a sectional side elevation view of the multi-axis prostheticankle of FIG. 42, taken along lines F-F thereof; and

FIG. 46 is a bottom plan view of the multi-axis prosthetic ankle of FIG.42.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT(S)

A first exemplary embodiment of a multi-axis prosthetic ankle accordingto the present invention can be observed by reference to FIGS. 1-9. Ascan be seen, particularly with respect to FIGS. 2-3, for clarity ofillustration the elastomeric casing is shown in phantom lines, therebyrevealing the encased components of the mechanical device (rigidmechanical means). In this particular embodiment, the main components ofthe multi-axis prosthetic ankle 5 are the bottom component 10, the lowerleg connection component 20, the mechanical device 30 (rigid mechanicalmeans), and the elastomeric casing 40, which is bonded to the bottomcomponent and the lower leg connection component and floatingly encasesthe elements of the mechanical device.

Referring more particularly to FIGS. 7 and 8, the bottom component 10comprises a generally circular disk like base 12, and a first “U” shapedbracket 14 (first rigid element) projecting perpendicularly upwardlyfrom the base. The first bracket 14 extends generally diametrically onthe base and defines a slot like first aperture 16 having respective topand bottom surfaces 16 a and 16 b. The base 12 and first bracket 14 arepreferably integrally formed from a rigid material such as stainlesssteel, but could be formed of any other rigid material such as titanium,aluminum or rigid plastic, for example. The base 12 preferably includesa threaded center hole 18 to accept a bolt or similar fastener for thesecurement of the bottom component 10 to a prosthetic foot.

The lower leg connection component 20 also has a generally circular disklike base 22, and has a pyramid part 24 projecting perpendicularlyupward from a central portion of the upper surface of the base 22 forconnection of the ankle joint to a lower leg prosthesis. The pyramidpart 24 may be of a generally conventional design. The lower legconnection component 20 is also preferably integrally formed ofstainless steel, but can also be formed of other rigid materialsincluding titanium, aluminum or rigid plastic. A lower portion 26 of thepyramid part 24 may be circular to accept a separate aluminum snap ondome 28.

A second bracket 31 (second rigid element) is mounted to the lowersurface of the base 22, for example by bolts 32 passing through boltholes 34 in the base 22 and the legs of the second bracket. The secondbracket 31 is also “U” shaped to define a slot like second aperture 36having, when mounted to the base 22, respective top and bottom surfaces36 a and 36 b. Moreover, a shim 38 may be positioned between one leg ofthe bracket 31 and the bottom of the base 22, as will be explainedbelow. To this end, one of the legs 31 a a of the second bracket 31 maybe shorter than the other. The second bracket 31 is preferably formed ofaluminum alloy, but can be formed of other rigid materials, includingstainless steel, titanium or a hard plastic, for example.

During assembly of the multi-axis prosthetic ankle, the second bracket31 is interlockingly positioned within the slot like aperture 16 of thefirst bracket 14 to form the mechanical device 30, after which thesecond bracket 31 is bolted to the lower surface of the base 22 of thelower leg connection component 20 via the bolts 32 and the optional shim38. At this time, a shim 38 of a proper thickness is selected on thebasis described below, and is positioned between the end of the shorterone of the legs of the second bracket 31 and the lower surface of thebase 22. As will be readily understood by those skilled in the art, theshim has a through hole for the bolt 32, and the legs 31 a and 31 b ofthe second bracket 31 have respective threaded through holes 31 c and 31d. The resulting assembly is generally shown in FIGS. 1-3.

Subsequently, the assembly of the bottom component 10, lower legconnection component 20 and the second bracket 31 is placed within amold (not shown). At this time, the assembly of the lower leg connectioncomponent 20 and second bracket 31 is held in a slightly elevatedposition so that the surfaces 36 a and 36 b of the second aperture 36 donot contact either of the surfaces 16 a or 16 b of the first bracket 14.Instead, the second bracket 31 is held so as to float without contactwith the first bracket 14. While the ankle components are held in thisposition, an elastomeric material in a flowable state is injected orotherwise introduced into the mold and permitted to harden. Theelastomeric material is preferably a rubber, and more preferably athermoset rubber polymer having a high resistance and memory undercyclical loading. Non-limiting examples include butyl rubber,ethylene-propylene rubber, neoprene rubber, nitrile rubber,polybutadiene rubber, polyisoprene rubber, stereo rubber,styrene-butadiene rubber, natural rubber, or a combination of two ormore of these rubbers.

The elastomeric material thereby encases and bonds to the bottomcomponent 10, the lower leg connection component 20 and the mechanicaldevice 30 composed of the interlocking brackets 14 and 31. The rigidcomponents are thus fused together with the elastomeric material to forma flexible assembly. This allows for a smooth transition through theentire gait cycle of a user of the ankle, from heel strike, throughmidstance, to toe off. As can be seen from FIG. 9, the interlockingbrackets 14 and 31 do not contact one another but instead are floatinglybonded through the intermediary of an intervening portion 42 of theelastomeric material casing 40. The peripheral surfaces of the bases 12,22 of the bottom component 10 and the lower leg connection component 20,respectively, may have annular concave recesses 12 a, 22 a at theircircumferential peripheries. These annular recesses improve the grip ofthe rubber material bonded to the components 10, 20.

Once the above-described assembly and molding process is accomplished,the snap on dome 28 may be optionally mounted to the pyramid part 24.The completed multi-axis ankle assembly 5 can then be incorporated intoa lower leg prosthesis in a conventional manner.

The elastomeric casing 40 may optionally include a protrudingenlargement 60 at the posterior part of the ankle 5. The protrudingenlargement 60 acts as a tendon and serves to stiffen the ankle 5 whenthe toe of an attached prosthetic foot is loaded.

By selecting a shim 38 of the proper thickness, one can control thethickness of the elastomeric material 42 in the spaces which separatethe first and second brackets 14, 31. One can thereby control thecompliance of the joint depending upon the expected loads, which can beanticipated by the weight and general physical activity level of theintended user. This done by selecting a shim 38 (or shims) of athickness that will provide a desired height “H” for the aperture 36,which allows for a predetermined spacing between the brackets 14, 31,and by the selection of the hardness of the elastomeric casing material40. A shore hardness A of between 70 and 99 is typically selected foradults, whereas a shore hardness A of between 50 and 70 is typicallyselected for children. For easy reference, the snap on dome 28 can becolor coded to the rubber hardness.

The angular degree of rotational motion between the bottom component 10and the lower leg connection component 20 is preferably limited bystops. In one embodiment, the stops take the form of a limit of thecompression of the elastomeric material 40 that is caused by the turningof the interlocking brackets 14, 31. That is, by selecting a proper shimto provide a desired height “H” for the aperture 36, one also selectsthe resulting thickness of the elastomeric material present between thebrackets, (e.g., the intervening elastomeric material 42). As the ankle5 pivots during ambulation, the rigid surfaces of the brackets 14, 31approach one another while compressing the intervening elastomericcasing material. The resistance of the elastomeric material to furthercompression increases as the ankle pivots. When this resistance equalsthe turning load on the ankle, the elastomeric material acts as a fixedstop against further rotation. Since the expected load on the ankle andthe compression resistance of the elastomeric material are known, oneskilled in the art can select a shim for a desired height “H” to permita predetermined rotation stop for the ankle. Of course, other forms ofthe rigid stops could instead be used.

The ankle 5 according to this embodiment of the present invention has ahigher load range of increasing moment of resistance compared to priorart ankles, which flatten out over lower load ranges. Preferable limitsof movement permitted by the stops of this particular embodiment of theankle 5 are as follows:

-   -   Internal/External rotation: 15°/15° (30° total).    -   Plantar flexion: 15°.    -   Dorsi flexion: 15°.    -   Inversion/Eversion: 10°/10° (20° total).    -   Anterior/Posterior translation:±0.10 to 0.375 inches.    -   Medial/Lateral translation:±0.05 to 0.250 inches.    -   Vertical displacement: 0.030 to 0.375 inches.        It should be understood that the above limits of movement have        been provided for purposes of illustration only, and the ankle 5        to which the limits apply can be designed to have other limits        of movement as well.

An alternate embodiment of a multi-axis prosthetic ankle 100 of thepresent invention is depicted in FIGS. 10-20. This particular embodimentof the multi-axis prosthetic ankle 100 is well suited to use with alow-profile prosthetic foot, such as a prosthetic foot that may be usedby an amputee having a long residual limb.

The multi-axis prosthetic ankle 100 can be seen to include a bottom,prosthetic foot connection component 110, that is adapted for attachmentto a prosthetic foot, and a lower leg connection component 130 that isadapted to attach the ankle to another prosthetic leg component.

The prosthetic foot connection component 110 is essentially a box-likestructure having rigid vertical walls 112 that bound a receiving cavity114. Although not shown in the drawing figures, the prosthetic footconnection component 110 may also have a bottom wall. Threaded orunthreaded bores 116 may also be provided through the prosthetic footconnection component 110 to facilitate its attachment to a prostheticfoot. A bottom surface 118 of the prosthetic foot connection component110 may be angled to allow for connection of the prosthetic footconnection component to a like-angled portion of a prosthetic foot,while simultaneously maintaining a top surface 120 of the prostheticfoot connection component in a substantially level position. Theprosthetic foot connection component 110 may be integrally formed oftitanium, but can also be formed or machined from other rigid materials,including stainless steel, aluminum, or rigid plastic, for example.

The receiving cavity 114 of the prosthetic foot connection component 110is designed to receive the connecting projection 140 of the lower legconnection component 130. More specifically, the receiving cavity 114 ofthe prosthetic foot connection component 110 is designed to allow aconnecting projection 140 of the lower leg connection component 130 tofloatingly reside therein when the two components are properlyassembled. As will be explained in more detail below, this design allowsthe positional relationship between the prosthetic foot connectioncomponent 110 and the lower leg connection component 130 to bemaintained by an elastomeric material, as opposed to a direct mechanicalconnection between the two components. During ambulation of the user,the connecting projection 140 is able to move within the receivingcavity 114, allowing for flexion of the ankle 100.

This particular embodiment of the lower leg connection component 130 isshown to have a generally circular, disk-like base 132, although othershapes are also possible. A pyramid part 134 may be affixed/integral tothe base and may project upward from a central dome-like portionthereof. The pyramid part 134 can be used to connect the ankle 100 toanother prosthetic leg component. The pyramid part 134 may be of agenerally conventional design.

Extending downward from the base 132 of the lower leg connectioncomponent 130 is a connecting projection 140. The connecting projection140 is provided to secure the lower leg connection component 130 withinan elastomeric material. The connecting projection 140 is also a rigidcomponent, and is firmly affixed to the base 132. Preferably, theconnecting projection 140 is integrally formed with the base 132, suchas by molding or machining. In this particular embodiment of the ankle100, the connecting projection 140 is shown to have a body that isgenerally rectangular in shape, except for a protrusion 142 extendingtherefrom. Although the protrusion 142 is shown to substantially form ahook shape when combined with the remainder of the connecting projection140 body, other shapes are also possible. The connecting projection 140is also shown to have a thickness that is significantly less than thediameter of the base 132. Of course, other shapes and thicknesses arealso possible. The protrusion 142 extends laterally outward from oneside of the connecting projection 140, such that a ledge 144 is formed.When assembled, the protrusion 142 is directed toward the posterior ofthe ankle 100. The connecting projection 140 may also have an aperture146 passing therethrough, or partially therethrough. The aperture 146provides for increased retention of the connecting projection 140 by theelastomeric material that will eventually surround much of the anklecomponents.

The lower leg connection component 130 is also preferably integrallyformed of titanium, but can also be formed or machined from other rigidmaterials, including, stainless steel, aluminum, or rigid plastic, forexample.

The ankle 100 is assembled by installing the lower leg connectioncomponent 130 to the prosthetic foot connection component 110. While itis described that the lower leg connection component 130 is “installed”to the prosthetic foot connection component 110, it should be realizedthat there is no direct connection of the components. Rather,“installed” merely refers to positioning the lower leg connectioncomponent 130 such that the connecting projection 140 properly resideswithin the receiving cavity 114. This relationship can best be observedby reference to the sectional view of FIG. 30. As can be seen, when thecomponents 110, 130 are properly arranged, the ledge 144 on theprotrusion 142 of the connecting projection 140 is preferably in closeproximity to a stop 126 formed by a recess 122 in a posterior verticalwall 112 of the body component, thereby permitting only a small amountof elastomeric material will be present between the ledge and the stop.Simultaneously, the base 132 of the lower leg connection component 130is substantially parallel to the top surface 120 of the prosthetic footconnection component 110. Hence, it can be understood that theprosthetic foot connection component 110 and the lower leg connectioncomponent 130 are not in direct contact. In an alternate embodiment, theprosthetic foot connection component 110 and the lower leg connectioncomponent 130 may be arranged such that the finalized ankle 100 has alarger amount of elastomeric material residing between the ledge 144 andthe stop 126.

Accordingly, by the above-described arrangements of the prosthetic footconnection component 110 and the lower leg connection component 130,there will generally be a gap between a bottom surface 134 of the lowerleg connection component base 132 and the top surface 120 of theprosthetic foot connection component 110. A flexion stop 136 ispreferably located within this gap. The flexion stop 136 may be aseparate component, or may be integrated or otherwise affixed to theprosthetic foot connection component 110. The flexion stop 136 may be ofcircular cross section to receive a portion of the disk-like base 132 ofthe lower leg connection component 130. The flexion stop 136 operates asa limit to flexion of the ankle.

Subsequent to installation of the lower leg connection component 130 andthe flexion stop 136 to the prosthetic foot connection component 110,the assembly thereof is placed within a mold (not shown). The mold isadapted to maintain the lower leg connection component 130 and theprosthetic foot connection component 110 substantially in the positionshown in FIG. 30, and described above. With the components 110, 130 heldin this position, an elastomeric material, preferably in a flowablestate, is injected or otherwise introduced into the mold and permittedto solidify. The elastomeric material is preferably a rubber, and morepreferably a thermoset rubber polymer having a high resistance andmemory under cyclical loading. Non-limiting examples include butylrubber, ethylene-propylene rubber, neoprene rubber, nitrile rubber,polybutadiene rubber, polyisoprene rubber, stereo rubber,styrene-butadiene rubber, natural rubber, or a combination of two ormore of these rubbers.

The elastomeric material thereby encases and/or bonds to the prostheticfoot connection component 110 and the lower leg connection component130. The elastomeric material may also encase and/or bond to the flexionstop 136. Introducing the elastomeric material to the component assemblyin this manner allows the elastomeric material to form a casing 146around the components (or portions thereof), and to fill voids betweenthe components. For example, any space within the cavity 114 that is notoccupied by the connecting projection 140 will be filled with theelastomeric material. Consequently, a flexible ankle assembly isproduced through retention of the ankle components by the elastomericmaterial. The flexibility of the assembly allows for a smooth transitionthrough the entire gait cycle of a user of the ankle, from heel strike,through midstance, to toe off. As can be better understood by referenceto FIG. 30, the prosthetic foot connection component 110 and the lowerleg connection component 130 are not directly connected to one anotherbut, instead, are floatingly connected through the intermediaryelastomeric material casing 146. For purposes of adhesion, theperipheral surface of at least the prosthetic foot connection component110 may have one or more recesses 110 a. These recesses improve the gripof the elastomeric material bonded to the exterior of the prostheticfoot connection component 110.

Once the above-described assembly and molding process is accomplished,the completed multi-axis ankle assembly 100 can be attached between aprosthetic socket and prosthetic foot.

The angular degree of rotational motion between the prosthetic footconnection component 110 and the lower leg connection component 130 ispreferably limited by fixed (mechanical) stops. In one embodiment, thefixed stops are formed by a combination of the abutment of theelastomeric material covered ledge 144 with the elastomeric materialcovered stop 126, and contact between the base 132 of the lower legconnection component with the flexion stop 136 or the top surface 120 ofthe prosthetic foot connection component 110. The fixed stop provided byabutment of the ledge 144 with the recess 122 in the wall 112 of theprosthetic foot connection component 110 is used to control the amountof toe lift that a prosthetic foot attached to the ankle 100 mayexperience.

During ambulation, compression of the elastomeric material resistsmovement (pivoting) of the ankle 100. The compression resistance of theelastomeric material increases as the angle of ankle 100 pivotincreases. When this resistance is equivalent to the turning (pivoting)load on the ankle 100, the elastomeric material may also act as a fixedstop against further rotation. One skilled in the art can use dataregarding the expected load on the ankle 100 and the compressionresistance of the elastomeric material to optimize the design of theankle.

As can be seen in the sectional view of FIG. 20, a reinforcing material124 can be installed to the top surface 120 of the prosthetic footconnection component 110. Alternatively, the reinforcing material 124may be installed to the top surface of the dorsi-flexion stop 136. Thereinforcing material 124 acts to protect the elastomeric material fromerosion due to contact with the moving base 132 of the lower legconnection component 130. The reinforcing material 124 may be, forexample, a section of Kevlar® mat, or a may be comprised of anothersimilarly abrasion resistant material, or combination of materials.

As can also be seen in the sectional view of FIG. 20, a locking pin 128or similar element may be optionally inserted into the prosthetic footconnection component 110 after the connecting projection 140 of thelower leg connection component 130 is inserted into the cavity 114therein. The locking pin 128 ensures that the connecting projection 140cannot be withdrawn from the cavity 114. Consequently, the locking pin128 also ensures that the prosthetic foot connection component 110 andthe lower leg connection component 130 cannot thereafter be separated.

The ankle 100 according to this embodiment of the present invention hasa higher load range of increasing moment of resistance compared to priorart ankles, which flatten out over lower load ranges. Exemplary limitsof movement permitted by the stops of this particular ankle 100 are asfollows:

-   -   Internal/External rotation: 18°/18° (36° total).    -   Plantar flexion: 15°.    -   Dorsi flexion: 5°.    -   Inversion/Eversion: 5°/5° (10° total).    -   Anterior/Posterior translation: 0.0 to 0.05 inches.    -   Medial/Lateral translation: 0.00 to 0.05 inches.    -   Vertical displacement: 0.07 inches.        It should be understood that the above limits of movement have        been provided for purposes of illustration only, and the ankle        100 to which the limits apply can be designed to have other        limits of movement as well.

As can be understood from a reading of the above description andreference to the drawing figures related to the ankles 5, 100, duringwalking, relative motion (translation and multi-axis rotation) betweenthe component 10, 110 mounted to the prosthetic foot, and the component20, 130 coupled to the prosthetic socket is permitted by the elasticdeformation of the elastomeric material. The motion is thus polycentricand multi-axial, with no fixed center of rotation or translation.Moreover, surface-to-surface contact that could lead to a breakdown ofthe material used to manufacture the rigid components of each ankle 5,100 has been eliminated. For example, even the small gap between theledge 144 and the stop 126 is preferably filled with elastomericmaterial. In addition to allowing relative motion (translation andmulti-axis rotation) between the component 10, 110 mounted to theprosthetic foot and the component 20, 130 coupled to the prostheticsocket, the elastomeric material also absorbs impact energies and,therefore, further acts as a vibration dampening device.

Variations of yet another embodiment of a multi-axis prosthetic ankle150, 200 of the present invention are illustrated in FIGS. 21-30 and31-41, respectively. Unlike the previously-described prosthetic ankles5, 100, these embodiments of the multi-axis prosthetic ankle 150, 200employ a direct mechanical connection between components thereof.

The multi-axis prosthetic ankle 150 of FIGS. 21-30 can be seen toinclude a bottom, prosthetic foot connection component 160, that isadapted for attachment to a prosthetic foot, and a lower leg connectioncomponent 180 that is adapted to couple the ankle 150 to a prostheticsocket component, such as by means of a prosthetic pylon or the like.

The prosthetic foot connection component 160 is essentially formed by apair of spaced apart and upwardly-extending support arms 164, having afirst end thereof attached to a base 162. The base 162 and the pair ofsupport arms 164 combine to form a mounting bracket for attaching theankle 150 to a prosthetic foot, and for pivotally retaining the lowerleg connection component 180. A retaining pin receiving aperture 166 islocated in each of the upwardly-extending support arms 164. As can bebest observed in FIGS. 23 and 26, a dorsi-flexion limiting slot 168 isalso located in each of the upwardly-extending support arms 164. Athreaded or unthreaded bore(s) 174 may be located in the base 162 tofacilitate attachment of the ankle 150 to a prosthetic foot. Theprosthetic foot connection component 160 may be integrally formed ofaluminum, but can also be formed or machined from other rigid materials,including titanium, stainless steel, or rigid plastic, for example.

A space 170 between the pair of support arms 164 is provided to receivea downwardly-extending connecting projection 190 of the lower legconnection component 180. More specifically, the space 170 between thepair of support arms 164 is designed to allow the connecting projection190 of the lower leg connection component 180 to reside therein, whilemaintaining some predetermined space between each support arm. As willbe explained in more detail below, the connecting projection 190 ismechanically coupled to the support arms 164 of the prosthetic footconnection component 160 in this embodiment of the ankle 150. Duringambulation of the user, the connecting projection 190 is able to movewithin the space 170, allowing for flexion of the ankle 150.

As can best be observed in FIGS. 27-29, this embodiment of the lower legconnection component 180 may have a generally circular, disk-like base182—although other shapes are also possible. A pyramid part 184 mayproject upward from a central dome-like portion of the base. The pyramidpart 184 may be of a generally conventional design.

Extending downward from the base 182 of the lower leg connectioncomponent 180 is the connecting projection 190. The connectingprojection 190 is provided to pivotally connect the lower leg connectioncomponent 180 to the prosthetic foot connection component 160. Theconnecting projection 190 is a rigid component, and is firmly affixed tothe base 182. Preferably, the connecting projection 190 is integrallyformed with the base 182, such as by molding or machining. In thisparticular embodiment, the connecting projection 190 is shown to have abody that is generally rectangular in shape, except for a protrusion 192extending from a lower portion thereof. The connecting projection 190 isalso shown to have a thickness that is less than the space 170 betweenthe support arms 164. It should be understood, however, that theconnecting projection 190 can be of virtually any size and shape thatallows it to adequately move within the space 170 between the supportarms 164. An aperture, preferably a bearing receiving aperture 194, islocated in the connecting projection 190 such that its center will alignwith the aligned centerlines of the retaining pin receiving apertures166 in the prosthetic foot connection component support arms 164.

In this embodiment of the ankle 150, the protrusion 192 extendssufficiently from the main body of the connecting projection 190 suchthat, after ankle assembly, the protrusion will pass over at least aportion of the dorsi-flexion limiting slots 168 when the ankle ispivoted about its retaining pin. The dorsi-flexion limiting slots 168are adapted to moveably retain a dorsi-flexion limiting pin 172. Thedorsi-flexion limiting slots 168 and dorsi-flexion limiting pin 172operate in conjunction with an elastomeric material to help control andlimit dorsi-flexion of the ankle (as described in more detail below).

The lower leg connection component 180 is also preferably integrallyformed of titanium, but can be formed or machined from other rigidmaterials, including, stainless steel, aluminum, or rigid plastic, forexample.

The ankle 150 is assembled by first installing a bearing 196 to thebearing receiving aperture 194 (when a bearing is used) of theconnecting projection 190. Preferably, the bearing 196 is a sphericalbearing to allow for a greater range of motion of the lower legconnection component 180. Preferably, the bearing 196 is force or pressfit into the bearing receiving aperture 194 of the projecting connection190. With the bearing 194 in place, the projecting connection 190 isinserted into the space 170 between the support arms 164 of theprosthetic foot connection component 160, such that the retaining pinreceiving apertures 166 in the support arms are aligned with the bore inthe bearing. With the components thus aligned, a retaining pin 198 isinserted through the receiving apertures 166 and the bearing 196.Preferably, the receiving apertures 166 are sized so as to securely gripthe ends of the retaining pin 198 once it is installed. Alternatively,clips or other retainers could be installed on the ends of the pin 198to maintain the position thereof. As can be best observed by referenceto FIG. 22, when properly installed, the connecting projection 190 andthe bearing 196 should be substantially centered along the length of theretaining pin 198 and within the space 170 between the support arms 164of the prosthetic foot connection component 160.

The dorsi-flexion limiting pin 172 may next be installed into thedorsi-flexion limiting slot 168, although such may be accomplished priorto assembly of the components 160, 180, as well. In a neutral positionof the assembled ankle 150, the protrusion 192 is in contact with thedorsi-flexion limiting pin 172 while the dorsi-flexion limiting pinresides at a posterior end of the dorsi-flexion limiting slot 168, andwhile the base 182 of the lower leg connection component 180 issubstantially level. The neutral position of the assembled ankle 150 canbest be observed by reference to FIGS. 23 and 30. It is generallypreferred that a small amount of elastomeric material exist between theprotrusion 192 and the dorsi-flexion limiting pin 172, and between theflexion limiting pin and the walls of the flexion limiting slots 168.

Subsequent to coupling of the prosthetic foot connection component 160to the lower leg connection component 180, and installation of thedorsi-flexion limiting pin 198, the assembly of components is placedwithin a mold (not shown). The mold is adapted to maintain thecomponents in the neutral position shown in FIGS. 23 and 30, anddescribed above. With the components held in this position, anelastomeric material in a flowable state is injected or otherwiseintroduced into the mold and permitted to harden. The elastomericmaterial is preferably a rubber, and more preferably a thermoset rubberpolymer having a high resistance and memory under cyclical loading.Non-limiting examples include butyl rubber, ethylene-propylene rubber,neoprene rubber, nitrile rubber, polybutadiene rubber, polyisoprenerubber, stereo rubber, styrene-butadiene rubber, natural rubber, or acombination of two or more of these rubbers.

The elastomeric material thereby forms a casing 188 around, and/or bondsto the prosthetic foot connection component 160 and the lower legconnection component 180. The elastomeric material also encases andbonds to the dorsi-flexion limiting pin 172, the spherical bearing 196(if present), and the retaining pin 198, and fills in the space 170between the support arms 164 and the unoccupied portion of thedorsi-flexion limiting slots 168.

Once the above-described assembly and molding process is accomplished,the completed multi-axis ankle assembly 150 can be installed between aprosthetic socket and prosthetic foot in a conventional manner.

Introducing the elastomeric material to the component assembly in theabove-described manner allows the elastomeric material to provide acontrolling resistance to plantar flexion, dorsi flexion, inversion,eversion, translation and internal/external rotational movement of aprosthetic foot to which the ankle 150 is attached. Resistance to suchmovement is provided by a corresponding compression of the elastomericmaterial. The compression resistance of the elastomeric materialincreases as the angle of ankle 150 pivot increases. When thisresistance is equivalent to the turning (pivoting) load on the ankle150, the elastomeric material may act as a fixed stop against furtherrotation. One skilled in the art can use data regarding the expectedload on the ankle 150 and the compression resistance of the elastomericmaterial to optimize the design of the ankle. Dorsi-flexion is furthercontrolled through resistance to movement of the protrusion 192 by theelastomerically held dorsi-flexion limiting pin 172. The dorsi-flexionlimiting pin 172 also acts as a fixed stop to dorsi-flexion when theelastomeric material residing in the flexion limiting slots 168 reachesits compression limit. Hard (mechanical) stops to movement of the ankle150 may also be provided by the elastomeric material coveredinward-facing walls of the support arms 164, and/or by spanning thespace between the support arms with a web of rigid material.

It should be further understood that the total amount of dorsi-flexioncan be controlled by adjusting the length of the dorsi-flexion limitingslot 168. For example, shortening the dorsi-flexion limiting slot 168will result in a reduction in the total amount of dorsi-flexion that canbe provided by the ankle 150. Conversely, lengthening the dorsi-flexionlimiting slot 168 will result in an increase in the total amount ofdorsi-flexion that can be provided by the ankle 150.

The design of the ankle 150, in conjunction with use of the elastomericmaterial, allows for a smooth transition through the entire gait cycleof a user of the ankle; from heel strike, through midstance, to toe off.In addition, the elastomeric material absorbs impact energies and,therefore, also acts as a vibration dampening device.

As can be understood from the foregoing description, the prosthetic footconnection component 160 and lower leg connection component 180 of theankle 150 are mechanically connected to one another via the retainingpin 198. When no spherical bearing is used, movement such asinternal/external rotation, inversion/eversion, and medial/lateraltranslation may be permitted by providing an aperture in the connectingprojection 180 that is sized to allow relative movement of theconnecting projection about the retaining pin 198. When used, thespherical bearing 196 facilitates such ankle movement, and in a morecontrolled manner. Use of the spherical bearing 196 and the elastomericmaterial, and provision of the space 170 between the connectingprojection 190 and the support arms 164 additionally minimizes oreliminates surface-to-surface contact between the components. Therefore,the design of the ankle 150 also reduces or eliminates the type ofsurface-to-surface contact that could lead to a breakdown of thematerial used to manufacture the rigid components of the ankle.

The ankle 150 according to this embodiment of the present invention hasa higher load range of increasing moment of resistance compared to priorart ankles, which flatten out over lower load ranges. Exemplary limitsof movement permitted by the stops of this particular embodiment of theankle 150 are as follows:

-   -   Internal/External rotation: 5°/5° (10° total).    -   Plantar flexion: 13°.    -   Dorsi flexion: 4°.    -   Inversion/Eversion: 8°.    -   Anterior/Posterior translation: None.    -   Medial/Lateral translation: 0.00 to 0.05 inches.    -   Vertical displacement: None.        It should be understood that the above limits of movement have        been provided for purposes of illustration only, and the ankle        150 to which the limits apply can be designed to have other        limits of movement as well.

Like the multi-axis prosthetic ankle 150 of FIGS. 21-30, the multi-axisprosthetic ankle 200 of FIGS. 31-41 can be seen to include a bottom,prosthetic foot connection component 210 that is adapted for attachmentto a prosthetic foot, and a lower leg connection component 230 that isadapted to couple the ankle 200 to a prosthetic socket component, suchas by means of a prosthetic pylon or the like.

The prosthetic foot connection component 210 is essentially formed in alike manner to the prosthetic foot connection component 160 of the ankle150 of FIGS. 21-30: with a pair of spaced apart and upwardly-extendingsupport arms 214, having one end thereof attached to a base 212. Thebase 212 and the pair of support arms 214 again combine to form amounting bracket for attaching the ankle 200 to a prosthetic foot, andfor pivotally retaining the lower leg connection component 230. A space220 is formed between the support arms 214 for receiving a connectingprojection 240 of the lower leg connection component 230. A retainingpin receiving aperture 216 is located in each of the upwardly-extendingsupport arms 214. As can be best observed in FIGS. 33 and 36, a flexionlimiting aperture 218 is also located in each of the upwardly-extendingsupport arms 214. A threaded or unthreaded bore(s) 222 may be located inthe base 212 to facilitate attachment of the ankle to a prosthetic foot.

This embodiment of the lower leg connection component 230 may also havea generally circular, disk-like base 232, although other shapes are alsopossible. The base 232 may have a pyramid part 234 projecting upwardfrom a dome-like central portion thereof. The pyramid part 234 can beused to connect the ankle 200 to a prosthetic pylon or some othercomponent that acts to couple the ankle to the prosthetic socket. Thepyramid part 234 may be of a generally conventional design.

Extending downward from the base 232 of the lower leg connectioncomponent 230 is a connecting projection 240, that is again provided topivotally connect the lower leg connection component 230 to theprosthetic foot connection component 210. The connecting projection 240is again rigid component that is firmly affixed to, or integrally formedwith the base 232. In this particular embodiment, the connectingprojection 240 is shown to have a body that tapers inward as it extendsdownward from its point of connection to the base 232, toward its distalend 242. An aperture, preferably a bearing receiving aperture 248 islocated in the connecting projection 240 such that its center will alignwith the aligned centerlines of the retaining pin receiving apertures216 in the prosthetic foot connection component support arms 214. A pinreceiving aperture 244 is located near the distal end 242 of theconnecting projection to receive a flexion limiting pin 246. Theconnecting projection 240 is again shown to have a thickness that isless than the space 220 between the support arms 214. It should beunderstood, however, that the connecting projection 240 can be ofvirtually any size and shape that allows it to adequately move withinthe space 220 between the support arms 214.

The prosthetic foot connection component 210 is preferably formed ofaluminum, while the lower leg connection component 230 is preferablyformed of titanium. However, each component 210, 230 can also be formedor machined from other rigid materials, including titanium, stainlesssteel, aluminum, or rigid plastic, for example.

The ankle 200 shown in FIGS. 31-41 is assembled in substantially thesame manner as the ankle 150 shown in FIGS. 21-30. The primarydifference between the two ankles is that a flexion limiting pin 246 isinstalled to the connecting projection 240 of this embodiment of theankle 200, as opposed to installation of a flexion limiting pin 172 tothe slot 168 in the support arms 164 of the previously described ankle150. Hence, once the prosthetic foot connection component 210 and thelower leg connection component 230 of the ankle 200 have been connectedusing the retaining pin 198, the flexion limiting pin 246 is passedthrough the flexion limiting aperture 218 in one of the support arms 214and installed to the pin receiving aperture 244 in the connectingprojection 240. Preferably, the flexion limiting pin 246 is retained bythe connecting projection 240 in a position such that each end of thepin resides at least partially within a corresponding one of the flexionlimiting apertures 218. Preferably, the flexion limiting pin 246 isforce or press fit to the pin receiving aperture 244 so that it cannotbe easily dislodged.

In a neutral (midstance) position of this embodiment of the assembledankle 200, the base 232 of the lower leg connection component 230 issubstantially level, and the ends of the flexion limiting pin 246 residewithin the flexion limiting apertures 218 in corresponding support arms214. The neutral position of the assembled ankle 200 can best beobserved by reference to FIGS. 33, 40 and 41 a.

Subsequent to coupling of the prosthetic foot connection component 210to the lower leg connection component 230, and installation of theflexion limiting pin 246, the assembly of components is placed within amold (not shown). The mold is preferably adapted to maintain thecomponents in the neutral position shown in FIGS. 33, 40 and 41 a, anddescribed above. With the components held in this position, anelastomeric material in a flowable state is injected or otherwiseintroduced into the mold and permitted to harden. The elastomericmaterial is preferably a rubber, and more preferably a thermoset rubberpolymer having a high resistance and memory under cyclical loading.Non-limiting examples include butyl rubber, ethylene-propylene rubber,neoprene rubber, nitrile rubber, polybutadiene rubber, polyisoprenerubber, stereo rubber, styrene-butadiene rubber, natural rubber, or acombination of two or more of these rubbers. It is also possible to moldthe components while they are maintained in a flexed state. Morespecifically, the components may be molded in a position such that theresulting ankle will have a raised heel when in its neutral position.Such an ankle may be particularly appropriate for use with boots, highheel shoes, and other footwear having a similar forward slope.

The elastomeric material thereby forms a casing 250 around, and/or bondsto, the prosthetic foot connection component 210 and the lower legconnection component 230. The elastomeric material also encases andbonds to the flexion limiting pin 246, the spherical bearing 196 (ifused) and the retaining pin 198, and fills in the space 220 between thesupport arms 214 and the unoccupied portion of the flexion limitingapertures 218.

Once the above-described assembly and molding process is accomplished,the completed multi-axis ankle assembly 200 can be installed between aprosthetic socket and prosthetic foot in a conventional manner.

Introducing the elastomeric material to the component assembly in thismanner allows the elastomeric material to provide a controllingresistance to plantar flexion, dorsi flexion, inversion, eversion,translation and internal/external rotational movement of a prostheticfoot to which the ankle 200 is attached. Resistance to such movement isprovided by a corresponding compression of the elastomeric material. Thecompression resistance of the elastomeric material increases as theangle of ankle 200 pivot increases. When this resistance is equivalentto the turning (pivoting) load on the ankle 200, the elastomericmaterial may act as a fixed stop against further rotation. One skilledin the art can use data regarding the expected load on the ankle 200 andthe compression resistance of the elastomeric material to optimize thedesign of the ankle.

In this embodiment of the ankle 200, the limit of both dorsi-flexion andplantar-flexion is further controlled by the size and location of theflexion limiting aperture 218 in the support arms 214. As can be bestunderstood by reference to FIGS. 33, 40, and 41 a-41 c, a flexionlimiting aperture 218 of smaller diameter would allow for less totaldorsi/plantar-flexion, while a flexion limiting aperture 218 of greaterdiameter would allow for more total dorsi/plantar flexion. Additionally,each of dorsi-flexion and plantar-flexion can be allocated a differentpercentage of the total available movement in such direction. Forexample, when the center of each flexion limiting aperture 218 islocated at the mid-line of the support arms 214 (i.e., substantially inline with the center of the retaining pin 198), the amount ofdorsi-flexion and plantar-flexion will be essentially equal. By shiftingthe center of the flexion limiting apertures 218 toward the anterior orposterior of the ankle 200, however, the amount of dorsi-flexion andplantar-flexion can be made to be unequal. For example, as shown inFIGS. 41 a-41 c, the flexion limiting apertures 218 are shifted slightlyanterior to the midline of the ankle 200, which results in a totalamount of possible plantar-flexion that is greater than the totalpossible amount of dorsi-flexion. As shown in FIGS. 41 a-41 c, thediameter and location of the flexion limiting apertures 218 of thisparticular embodiment of the ankle 200 provides for approximately 12degrees of maximum flexion at heel strike and approximately 3 degrees ofmaximum flexion at toe off, for a total of 15 degrees of total movementin the dorsi/plantar-flexion plane. Therefore, as can be understood,greater or lesser amounts of dorsi-flexion and/or plantar-flexion arepossible by altering the diameter and/or location of the flexionlimiting apertures 218. It should also be understood that a similaradjustment to dorsi-flexion and/or plantar-flexion can be achieved bymanipulating the size and/or location of the flexion limiting pin 246,instead of the flexion limiting apertures 218. Alternatively, anadjustment to the size and/or location of both the flexion limitingapertures 218 and the flexion limiting pin 246 can also be made for thispurpose.

It should also be realized that resistance to dorsi-flexion andplantar-flexion occurs both as a result of compression of theelastomeric material by the connecting projection 240, and bycompression of the elastomeric material by the flexion limiting pin 246.Thus, the flexion limiting pin 246 not only acts as a fixed stop when itcauses the elastomeric material in the flexion limiting apertures 218 toreach its compression limit, it also acts as a means of controlledresistance to dorsi/plantar-flexion.

The design of the ankle 200, in conjunction with use of the elastomericmaterial, allows for a smooth transition through the entire gait cycleof a user of the ankle; from heel strike, through midstance, to toe off.In addition, the elastomeric material absorbs impact energies and,therefore, also acts as a vibration dampening device.

As can be understood from the foregoing description, the prosthetic footconnection component 210 and lower leg connection component 230 of theankle 200 are mechanically connected to one another via the retainingpin 198. When no spherical bearing is used, movement such asinternal/external rotation, inversion/eversion, and medial/lateraltranslation may be permitted by providing an aperture in the connectingprojection 240 that is sized to allow relative movement of theconnecting projection about the retaining pin 198. When used, thespherical bearing 196 facilitates such ankle movement, and in a morecontrolled manner. Use of the spherical bearing 196 and provision forthe space 220 between the connecting projection 240 and the support arms214 additionally minimizes surface-to-surface contact between thecomponents. Additionally, the flexion limiting pin's 246 compression ofthe elastomeric material within the flexion limiting apertures 218 canact as a hard stop, instead of compression of the elastomeric materialin the space 220 by the connecting projection 240. Therefore, the designof the ankle 200 also reduces or eliminates the type ofsurface-to-surface contact that could lead to a breakdown of thematerial used to manufacture the rigid components of the ankle.

The ankle 200 according to this embodiment of the present invention hasa higher load range of increasing moment of resistance compared to priorart ankles, which flatten out over lower load ranges. Exemplary limitsof movement permitted by the stops of this particular embodiment of theankle 200 are as follows:

-   -   Internal/External rotation: 5°/5° (10° total).    -   Plantar flexion: 13°.    -   Dorsi flexion: 4°.    -   Inversion/Eversion: 8°.    -   Anterior/Posterior translation: None.    -   Medial/Lateral translation: 0.0 to 0.05 inches.    -   Vertical displacement: None.        It should be understood that the above limits of movement have        been provided for purposes of illustration only, and the ankle        200 to which the limits apply can be designed to have other        limits of movement as well.

Still another embodiment of a multi-axis prosthetic ankle 300 of thepresent invention is illustrated in FIGS. 42-46. This embodiment of amulti-axis prosthetic ankle 300 can be seen to again include a bottom,prosthetic foot connection component 302, that is adapted for attachmentto a prosthetic foot, and a lower leg connection component 312 that isadapted for coupling of the ankle to a prosthetic socket, such as bymeans of a pylon or other suitable component.

The prosthetic foot connection component 302 of this embodiment isessentially a substantially hollow housing having rigid side walls 304that bound a receiving cavity 308. The prosthetic foot connectioncomponent 302 may also have a partial or complete bottom wall. As shown,the prosthetic foot connection component 302 has a bottom wall 306 withan aperture 310 passing therethrough. Threaded or unthreaded bores 334may also be provided in or through the prosthetic foot connectioncomponent 302 to facilitate its attachment to a prosthetic foot. In anembodiment of a prosthetic foot connection component having a complete,or substantially complete bottom wall, a single threaded or unthreadedbore may be present approximately at its center point. The prostheticfoot connection component 302 may be integrally formed of variousmaterials such as, for example, titanium, stainless steel, aluminum,rigid plastic or other suitable rigid materials.

The receiving cavity 308 of the prosthetic foot connection component 302is designed to receive a portion of a lower leg connection component312. The receiving cavity 308 may also be designed to receive one ormore retaining elements, examples of which are described in more detailbelow. During ambulation of a user, the lower leg connection component312 is able to move within the receiving cavity 308 in a manner thatallows for flexion of the ankle 300.

The lower leg connection component 312 is generally comprised of anelongated element having a first, or distal end 312 a adapted to residein the receiving cavity 308 after ankle assembly, and a second, orproximal end 312 b adapted to reside outside the receiving cavity 308after ankle assembly. The distal end 312 a of the lower leg connectioncomponent 312 is preferably designed to facilitate retention of thelower leg connection component in the receiving cavity. The proximal end312 b of the lower leg connection component 312 is preferably adaptedfor attachment to a prosthetic pylon or some other component used tocouple the ankle to a prosthetic socket. In the particular embodiment ofthe present invention, the proximal end 312 b of the lower legconnection component 312 is comprised of a pyramid adapter 316. Itshould be realized, however, that other types of connecting devices mayalso be used. The lower leg connection component 312 may be formed frommaterials alike or similar to the materials used to form the prostheticfoot connection component.

As can best be observed in FIGS. 43 and 45, this embodiment of the lowerleg connection component 312 has a distal end 312 a that is generallyflared outward. The distal end 312 a of the lower leg connectioncomponent 312 may also be of another shape that assists with itsretention in the receiving cavity 308. Preferably, but not necessarily,there are also one or more recesses or holes 313 in the flared distalend 312 a of the lower leg connection component 312. These recesses orholes 313 receive elastomeric material during the molding process thatassists with retention and/or helps to control movement of the of thelower leg connection component 312.

A shaft portion 314 extends upward from the distal end 312 a, eventuallyterminating at the proximal end 312 b in the pyramid adapter 316. Thepyramid adapter 316 may be of a generally conventional design.

An outwardly protruding lip 318 may reside between the distal end 312 aand the proximal end 312 b of the prosthetic foot connection component312. If present, the lip 318 may completely surround the shaft portion318 or may extend only partially therearound. Preferably, such a lip 318is also designed to engage an aperture present in a prosthetic dome 330that may be used with the ankle 300.

The exemplary embodiment of the ankle 300 shown in FIGS. 42-46 typicallyincludes several other components. Specifically, a retainer or retainingassembly is generally present within the receiving cavity to helpprevent withdrawal of said lower leg connection component 312 therefrom.Such a retainer or retaining assembly may be of various design. Forexample, and as shown, such a retainer or retaining assembly 319 maycomprise a separate element(s) that is installed into the receivingcavity 308 so as to engage the walls thereof. Alternatively, in certainembodiments, a retainer or retaining element may be formed directlyin/by the walls of the receiving cavity 308. In any event, the lower legconnection component 312 is securely retained in the receiving cavity bythe retainer.

In this particular embodiment of the ankle 300, the retaining assembly319 includes a retaining washer 320 that engages the distal end 312 a ofthe lower leg connection component 312 after installation into thereceiving cavity 308. Preferably, but not necessarily, the interior ofthe retaining washer 320 is shaped alike or similar to the upper surfaceof the distal end 312 a of the lower leg connection component 312. Theretaining washer 320 has an aperture passing therethrough for allowingpassage of a portion of the lower leg connection component 312. Theretaining washer 320 remains within the prosthetic foot connectioncomponent 302 after assembly of ankle 300. The retaining 320 washer maybe constructed from any of the materials described above as adequate formanufacturing the prosthetic foot connection component 302 or lower legconnection component 312, or may be manufactured from another suitableand, preferably rigid, material.

Although not essential to the present invention, an internal bearing 322may also be provided and located between the retaining washer 320 andthe distal end 312 a of the lower leg connection component 312. If used,the shape of the internal bearing 322 preferably reflects the shape ofthe upper surface of the distal end 312 a of the lower leg connectioncomponent 312 and the interior of the retaining washer 320. The internalbearing 322 has an aperture passing therethrough for allowing passage ofa portion of the lower leg connection component 312. The internalbearing 322 may be comprised of various materials, but is preferablyconstructed of a low friction material.

In this embodiment of the retaining assembly 319, an internal snap ring324 sits above the retaining washer 320 and seats in a receiving groove326 located along the interior wall(s) of the receiving cavity 308. Thesnap ring 324 keeps at least the retaining washer 320 and internalbearing 322 properly located within the receiving cavity 308, therebyalso assisting with retention of the lower leg connection component 312.

An external bearing 328 is preferably, but not necessarily, present. Theexternal bearing 328 has an aperture passing therethrough for allowingpassage of a portion of the lower leg connection component 312. As willbe described in more detail below, the size and/or shape of the aperturecan be adjusted to provide for different ranges of ankle motion. Theexternal bearing 328 preferably resides atop a section of elastomericmaterial. The external bearing 328 also preferably resides at leastpartially within the receiving cavity 308 of the prosthetic footconnection component 302, although in other embodiments the externalbearing may engage a top surface of the prosthetic foot connectioncomponent without entering the receiving cavity.

A prosthetic dome 330 may optionally be fitted over the proximal end 312b of the lower leg connection component 312 so that its underside restsatop or resides in close proximity to the top surface of the externalbearing 328. Such a dome 330 is generally umbrella-shaped, and would bewell known to one skilled in the art. The dome 330 has an aperturepassing therethrough for allowing passage of at least the pyramid part316 of the lower leg connection component 312. Preferably, the dome 330is configured to receive and engage at least the lip portion 318 of thelower leg connection component 312. During flexion of the ankle the dome330 moves along with the lower leg connection component 312, with atleast a portion of its underside typically riding over top of theexternal bearing 328. In another embodiment, the dome 330 can be usedwithout the external bearing 328, in which case the dome may rest atopthe elastomeric material 332—which may be of a shape that conforms tothe underside of the dome.

This particular embodiment of the ankle 300 is normally assembled byinserting the lower leg connection component 312, internal bearing 322,retaining washer 320, snap ring 324 and, optionally, the dome 330, intothe receiving cavity 308 of the prosthetic foot connection component 302such that the internal bearing is trapped between the lower legconnection component and the retaining washer and the snap ring entersthe receiving groove 326. Placing the dome 330 in the mold prior tomolding, while not necessary, may assist with controlling migration ofthe subsequently supplied elastomeric material.

This assembly of components is then placed into a special mold designedto receive the components and an amount of a subsequently suppliedelastomeric material. The mold is typically designed to restrict theelastomeric material to a particular hardened size and/or shape, and/orto limit the elastomer to contact with only certain predetermined areasof the assembly (as is illustrated by the completed ankle assembly ofFIG. 45). In particular, the mold may be designed to produce a column ofelastomeric material that extends upward around the lower leg connectioncomponent 312 and is subsequently received by the aperture in theexternal bearing 328.

With the components held in position, an elastomeric material in aflowable state is injected or otherwise introduced into the mold andpermitted to harden. The elastomeric material is preferably a rubber,and more preferably a thermoset rubber polymer having a high resistanceand memory under cyclical loading. Non-limiting examples include butylrubber, ethylene-propylene rubber, neoprene rubber, nitrile rubber,polybutadiene rubber, polyisoprene rubber, stereo rubber,styrene-butadiene rubber, natural rubber, or a combination of two ormore of these rubbers. The use of other elastomeric materials is alsopossible.

The elastomeric material 332 thereby forms a casing around, and/orotherwise bonds to at least a portion of any components present andexposed within the receiving cavity 308. The elastomeric material 332may also flow into the recesses or holes 313 in the prosthetic legconnection component, and the apertures of the retainer or retainingassembly 319 (such as the apertures in the internal bearing 322,retaining washer 320 and snap ring 324). A representative shape ofmolded elastomeric material 332 can be seen in FIGS. 43 and 45. Notethat the elastomeric material 332 shape shown in FIGS. 43 and 45 isintended to represent the elastic material as if removed intact from theprosthetic foot connection component after molding.

Once the above-described assembly and molding process is accomplished,the molded assembly is removed from the mold. The external bearing maythen be installed over the protruding pyramid adapter 316 and insertedat least partially into the receiving cavity 308, where it floats on topof the hardened elastomeric material 332. The dome 330 is then finallyinstalled over the top of the external bearing 328. In certainembodiments, the dome 330 may be retained on the ankle 300 by, forexample, a press fit to the optional lip 318 of the lower leg connectioncomponent 312, or by an adhesive. In such an embodiment, the dome 330 isgenerally responsible for securing the position of the external bearing328.

In another embodiment, the external bearing 328 may also be placed inthe mold such that the elastomeric material 332 bonds thereto. Forexample, the elastomeric material 332 may be allowed to contact theunderside of the external bearing 328 and to flow through the aperturepresent therein. In such a case, it may also be possible to contact andbond the elastomeric material to the dome 330.

Introducing the elastomeric material to the component assembly in theabove-described manner allows the elastomeric material to provide acontrolling resistance to plantar flexion, dorsi flexion, inversion,eversion, translation and internal/external rotational movement of aprosthetic foot to which the ankle 300 is attached. Resistance to suchmovement is provided by a corresponding compression of the elastomericmaterial. The compression resistance of the elastomeric materialincreases as the angle of ankle 300 pivot increases. When thisresistance is equivalent to the turning (pivoting) load on the ankle300, the elastomeric material may act as a fixed stop against furtherrotation. One skilled in the art can use data regarding the expectedload on the ankle 300 and the compression resistance of the elastomericmaterial to optimize the design of the ankle.

The overall range of ankle articulation can also be controlled bymanipulating the size of the space (gap) existing between the outsidesurface of the lower leg connection component 312 and the aperture inthe external bearing 328. More particularly, a reduced gap results inless elastomeric material being present therebetween and, consequently,in a reduced range of motion. Conversely, an increased gap results inmore elastomeric material being present therebetween and, an increasedrange of motion. The aperture in the external bearing 328 may be ofvirtually any shape, and may be of similar or dissimilar shape to theportion of the lower leg connection component 312 passing therethrough.The aperture may also be offset in order to limit certain types ofmotion (e.g., planar flexion, dorsi-flexion, inversion, eversion, etc.)and/or to increase others. Any combination of aperture size, shapeand/or offset may be provided to control articulation in a desiredmanner. The shape of an appropriate portion of the lower leg connectioncomponent 312 may also be manipulated for this purpose, whether inconjunction with, or in lieu of, manipulation of the size, shape and/oroffset of the aperture in the external bearing 328.

While certain embodiments of the present invention are described indetail above, the scope of the invention is not to be considered limitedby such disclosure, and modifications are possible without departingfrom the spirit of the invention as evidenced by the following claims:

1. A multi-axis prosthetic ankle, comprising: a prosthetic footconnection component containing a receiving cavity; a lower legconnection component, at least a first end thereof installed into saidreceiving cavity; a retainer located in said receiving cavity forpreventing upward displacement of said lower leg connection componentwith respect to said prosthetic foot connection component; and anelastomeric material in said receiving cavity and substantially encasingany components present therein; wherein said elastomeric material allowsfor controlled movement between said prosthetic foot connectioncomponent and said lower leg connection component.
 2. The multi-axisprosthetic ankle of claim 1, wherein said first end of said lower legconnection component is flared or otherwise enlarged to facilitateretention of said lower leg connection component within said receivingcavity.
 3. The multi-axis prosthetic ankle of claim 1, furthercomprising one or more recesses or holes in said first end of said lowerleg connection component for receiving said elastomeric material.
 4. Themulti-axis prosthetic ankle of claim 1, wherein said prosthetic footconnection component is a substantially hollow structure having rigidvertical walls.
 5. The multi-axis prosthetic ankle of claim 1, furthercomprising one or more threaded or unthreaded bores in said prostheticfoot connection component for facilitating its connection to aprosthetic foot.
 6. The multi-axis prosthetic ankle of claim 1, whereina second end of said lower leg connection component further includes apyramid adapter, said pyramid adapter for connecting said ankle to aprosthetic leg.
 7. The multi-axis prosthetic ankle of claim 1, furthercomprising an external bearing having an aperture through which aportion of said lower leg connection component passes, said externalbearing residing atop said elastomeric material and at least partiallywithin said receiving cavity.
 8. The multi-axis prosthetic ankle ofclaim 7, wherein elastomeric material is present within said aperture insaid external bearing.
 9. The multi-axis prosthetic ankle of claim 7,wherein the size and/or shape of said aperture in said external bearingis used to control the overall flexion range of said ankle.
 10. Themulti-axis prosthetic ankle of claim 7, wherein one or more walls ofsaid aperture in said external bearing acts as a mechanical stop thatlimits overall ankle flexion.
 11. The multi-axis prosthetic ankle ofclaim 7, further comprising a dome adapted for installation over saidlower leg connection component and for movement over a top surface ofsaid external bearing.
 12. The multi-axis prosthetic ankle of claim 1,wherein said retainer comprises a retaining washer and snap ring, saidsnap ring engaging a groove in said receiving cavity.
 13. The multi-axisprosthetic ankle of claim 12, further comprising an internal bearing forpreventing surface-to-surface contact between said retaining washer andsaid first end of said lower leg connection component.
 14. Themulti-axis prosthetic ankle of claim 1, wherein said retainer is anintegral part of said receiving cavity.
 15. The multi-axis prostheticankle of claim 1, wherein said elastomeric material is bonded to atleast said receiving cavity of said prosthetic foot connection componentand to said first end of said lower leg connection component.
 16. Themulti-axis prosthetic ankle of claim 1, wherein said elastomericmaterial is a polymer rubber.
 17. The multi-axis prosthetic ankle ofclaim 1, wherein said polymer rubber has a shore A hardness of 50 to 99.18. A multi-axis prosthetic ankle, comprising: a prosthetic footconnection component containing a receiving cavity; a relativelyelongated lower leg connection component having a distal end installedinto said receiving cavity and adapted to facilitate retention therein,and a proximal end located outside said receiving cavity and adapted toconnect said ankle to a prosthetic leg; a retainer located in saidreceiving cavity for preventing upward displacement of said lower legconnection component with respect to said prosthetic foot connectioncomponent; and an elastomeric material residing within said receivingcavity and substantially encasing any components present therein;wherein relative movement between said prosthetic foot connectioncomponent and said lower leg connection component of an assembled ankleassembly is damped by said elastomeric material.
 19. The multi-axisprosthetic ankle of claim 18, wherein said distal end of said lower legconnection component is flared outward.
 20. The multi-axis prostheticankle of claim 18, further comprising one or more recesses or holes insaid distal end of said lower leg connection component for receivingsaid elastomeric material.
 21. The multi-axis prosthetic ankle of claim18, wherein said prosthetic foot connection component is a substantiallyhollow structure having rigid vertical walls.
 22. The multi-axisprosthetic ankle of claim 18, further comprising one or more threaded orunthreaded bores in said prosthetic foot connection component forfacilitating its connection to a prosthetic foot.
 23. The multi-axisprosthetic ankle of claim 18, wherein said proximal end of said lowerleg connection component comprises a pyramid adapter.
 24. The multi-axisprosthetic ankle of claim 18, wherein said retainer comprises aretaining washer and snap ring, said snap ring engaging a groove in saidreceiving cavity.
 25. The multi-axis prosthetic ankle of claim 24,further comprising an internal bearing for preventing surface-to-surfacecontact between said retaining washer and said distal end of said lowerleg connection component.
 26. The multi-axis prosthetic ankle of claim18, wherein said retainer is comprised of an integral part of saidreceiving cavity.
 27. The multi-axis prosthetic ankle of claim 18,further comprising an external bearing having an aperture through whicha portion of said lower leg connection component passes, said externalbearing residing atop said elastomeric material and at least partiallywithin said receiving cavity.
 28. The multi-axis prosthetic ankle ofclaim 27, wherein elastomeric material substantially surrounds theportion of said lower leg connection component passing through saidaperture in said external bearing.
 29. The multi-axis prosthetic ankleof claim 28, wherein the size and/or shape of said aperture in saidexternal bearing is used to control the overall flexion range of saidankle.
 30. The multi-axis prosthetic ankle of claim 27, wherein one ormore walls of said aperture in said external bearing act as a mechanicalstop that limits overall ankle flexion.
 31. The multi-axis prostheticankle of claim 18, further comprising a lip extending outward from saidlower leg connection component, said lip residing outside of saidreceiving cavity and adapted to receive a prosthetic dome.
 32. Themulti-axis prosthetic ankle of claim 18, further comprising a prostheticdome adapted for installation over said lower leg connection componentand for movement over a top surface of said external bearing.
 33. Themulti-axis prosthetic ankle of claim 18, wherein said elastomericmaterial is bonded to at least said receiving cavity of said prostheticfoot connection component and to said distal end of said lower legconnection component.
 34. The multi-axis prosthetic ankle of claim 18,wherein said elastomeric material is a polymer rubber.
 35. Themulti-axis prosthetic ankle of claim 18, wherein said polymer rubber hasa shore A hardness of 50 to
 99. 36. A multi-axis prosthetic ankle,comprising: a prosthetic foot connection component comprising asubstantially hollow housing containing a receiving cavity; a relativelyelongated lower leg connection component having a flared distal endthereof installed into said receiving cavity, and a proximal end locatedoutside said receiving cavity and having a pyramid adapter forconnecting said ankle to a prosthetic leg; a retainer located in saidreceiving cavity and around said distal end of said lower leg connectioncomponent, said retainer assembly for preventing upward displacement ofsaid lower leg connection component with respect to said prosthetic footconnection component; and an elastomeric material substantially fillingsaid receiving cavity so as to substantially encase any componentspresent therein; whereby relative movement between said prosthetic footconnection component and said lower leg connection component iscontrolled by deformation of said elastomeric material.
 37. Themulti-axis prosthetic ankle of claim 36, further comprising one or morerecesses or holes in said distal end of said lower leg connectioncomponent for receiving said elastomeric material.
 38. The multi-axisprosthetic ankle of claim 36, further comprising one or more threaded orunthreaded bores in said prosthetic foot connection component forfacilitating its connection to a prosthetic foot.
 39. The multi-axisprosthetic ankle of claim 36, wherein said elastomeric material is apolymer rubber.
 40. The multi-axis prosthetic ankle of claim 39, whereinsaid polymer rubber has a shore A hardness of 50 to
 99. 41. Themulti-axis prosthetic ankle of claim 36, further comprising an externalbearing residing atop said elastomeric material and at least partiallywithin said receiving cavity, said external bearing having anelastomeric material containing aperture through which said proximal endof said lower leg connection component passes.
 42. The multi-axisprosthetic ankle of claim 41, wherein one or more walls of said aperturein said external bearing act as a mechanical stop that limits overallankle flexion.
 43. The multi-axis prosthetic ankle of claim 41, whereinthe size and/or shape of said aperture in said external bearing is usedto control the overall flexion range of said ankle.
 44. The multi-axisprosthetic ankle of claim 41, further comprising a dome having anaperture through which said proximal end of said lower leg connectioncomponent passes, said dome installed over said lower leg connectioncomponent and adapted for movement over a top surface of said externalbearing.
 45. The multi-axis prosthetic ankle of claim 44, furthercomprising a lip extending outward from said lower leg connectioncomponent, said lip residing outside of said receiving cavity andadapted to engage said prosthetic dome.
 46. The multi-axis prostheticankle of claim 36, wherein said retainer comprises a retaining washerand snap ring, said snap ring engaging a groove in said receivingcavity.
 47. The multi-axis prosthetic ankle of claim 46, furthercomprising an internal bearing for preventing surface-to-surface contactbetween said retaining washer and said distal end of said lower legconnection component.
 48. The multi-axis prosthetic ankle of claim 36,wherein said retainer is comprised of an integral part of said receivingcavity.
 49. A multi-axis prosthetic ankle, comprising: a prosthetic footconnection component comprising a substantially hollow housingcontaining a receiving cavity; a relatively elongated lower legconnection component having a flared distal end thereof installed intosaid receiving cavity, and a proximal end located outside said receivingcavity and having a pyramid adapter for connecting said ankle to aprosthetic leg; a retainer assembly comprising an internal bearing, aretaining washer and a snap ring installed into said receiving cavityand over said distal end of said lower leg connection component, saidretainer assembly for preventing upward displacement of said lower legconnection component with respect to said prosthetic foot connectioncomponent; an elastomeric material substantially filling said receivingcavity so as to substantially encase any components present therein; anexternal bearing residing atop said elastomeric material and at leastpartially within said receiving cavity, said external bearing having anelastomeric material containing aperture through which said proximal endof said lower leg connection component passes; and a dome having anaperture through which said proximal end of said lower leg connectioncomponent passes, said dome installed over said lower leg connectioncomponent and adapted for movement over a top surface of said externalbearing; whereby relative movement between said prosthetic footconnection component and said lower leg connection component iscontrolled by deformation of said elastomeric material.